Topic 2 Flashcards
What are the characteristics of life?
order regulation energy processing growth + development reproduction response to environment evolutionary adaption
What did Aristotle say?
species are fixed = unchanging
they are created perfectly matched to their environment
organized by complexity, with man on top
What is taxonomy and systematics?
nomenclature: a system of rules for naming things
taxonomy: the practice of naming + classifying organisms
systematics: the theory (and practice) of classifying organisms based on evolutionary history
What are the problems with common names?
different names for some species, common names differ among countries and languages, problem can occur within the same language and country
same name for different species
common name may imply relationships that do not exist
What is the Linnaen System?
use of Latin as universal language of scientific nomenclature
use of unique binomen as name of each species
classify and group species using hierarchical categories based on relatedness and/or similarity
What is a binomial name?
genus name, species name together make the binomial name
What are phylogenetic trees?
evolutionary tree that shows the evolutionary relationship between organisms (past and present)
also hypothesis for the evolutionary relationships
goal: to organize species into groups with common ancestory
What is a taxon?
named group at any level of classification
What is a clade?
a valid group includes the ancestor at any node and everything above and beyond it (descendants)
How do you interpret a phylogenetic tree?
relationships among taxa are interpreted from order in which branches split, not from how names of taxa are arranged at tips of branches
a tree can rotate at its nodes (like a mobile) without altering the relationships
What is the in group and out group in a phylogenetic tree?
in group: group whose relationships interested in untangling
out group: one or more taxa that are distinctly related to the in group, but that have diverged from it at an earlier time
What is character and state?
character: type of structure, behavior, DNA sequence, etc.
state: manifestation of that character
What is the principle of parsimony?
construct a set of nested relationships that minimize the number of times a character changes states
choose the phylogeny that requires the fewest number of evolutionary events —> because it is more probable
What is Occam’s Razor?
if one must postulate a number of unknowable events (changes in character states), the best hypothesis is the one requiring the fewest postulates
What is synapomorphy?
relative to non-vertebrates, presence of vertebrate is a synapomorphy (shared, derived state)
only synapomorphies are useful for reconstructing phylogenetic relationships
